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Sharpening carbide cutters on turning tools?

8K views 14 replies 8 participants last post by  kelvancra 
#1 · (Edited by Moderator)
Have any of you guys had success with this? I subscribe to Ethan's videos…He's talking with Jamie from Trend diamond sharpening. Seems simple enough but would love to hear an unbiased opinion.
 
#2 ·
Yes, diamond cards & stones work well for awhile, but eventually will have to replace carbide inserts or cutters. Lot of people use mineral oil or machine oil on their diamond cards & stones and some folks use plain water versus hoing oil.

Diamon cards or stones great for touching up an edge on turning tools too.

Diamond creidt card do where out faster than stones but less expensive.
 
#4 ·
Thanks for your input! Sounds like Trend is pretty well top of the line as far as diamonds go? Anyone have experience with trend diamond cards specifically?

- BandsawJeff
Trend is good … also DMT. I have had more experience with DMT … I think they are a horse apiece.
 
#5 · (Edited by Moderator)
The discussions I've heard is that , Yep, you can sharpen them, but it won't get you back to 100%. I didn't believe it, so decided to try it once I had dulled my cutters. I got a 300 and 600 grit card, and used oil like the video. Scrubbed my cutter on that card for awhile, and tried it. Seemed to cut a little better, but didn't feel as good as the factory edges.
So, I ended up buying cutters as I needed them. I have about 18 cutters now, all sizes, and have finally discovered how to actually sharpen carbide inserts.

Tucson has the Gem and Mineral Show come through every year. The town in inundated with rocks, fossils, minerals, and lapidary tools. Last years my intent was to get a couple 8" Lap Discs. 220 and 1000 grits. When I got home, I removed the nut holding the 80 grit CBN wheel, and inserted the 220 grit disc onto the arbor. On the 180 grit CBN wheel, I put the 1000 grit disc. When I have a need to sharpen my carbides, I remove it from the tool, hold it on the end of my finger and hold it up to the 220 grit lap disc. When it gets hot, I'm done with that grit. I pull my finger away, and then go to the 1000 grit and repeat. This takes about 10-15 seconds at the most. I actually think I did pretty good as it seems to cut cleaner than the factory cutters. I made a video and might post it one of these days.

This year I went back to the G&M show, and bought a couple more Lap Discs, a 320 and 600 grit. My CBN's are now sandwiched between diamond Lap Discs for any and all carbide sharpening's I might need. Heck, a couple days ago, I trimmed up a rock. The 4 discs I have cost $70. The 18 cutters cost over $300 and I think each carbide will allow at least 5 sharpening's each. . .... Jerry (in Tucson).
 
#6 ·
I have sharpened my carbide cutters with 300 then 600 and they seem pretty good. Then went to a higher grit and they did seem to be as sharp if not sharper than the original factory edge. By the way, 1000 was the higher grit I now go to. I'm on the 3rd sharpening and so far, so good. I realize that sooner or later I will have to buy new inserts.
 
#7 ·
I use a lapidary disc for most of my honing; it was made for standard tools but works with carbide also.It is 1000 or 1200 but a courser grit would be fine.
I picked up the disc and backing plate on the bay for about $20 and a new garage door motor replacement kit was an additional $20.
I like it because it is slow speed (74 rpm) so bits will not sling off. On the outside edge I have about 30 inches sliding under the bit per elephant. A couple is all it takes for carbide bits or any straight edge tools (skew, bedan, parting, 3 point, etc).
At about 1 round per second it is nice to cover with newspaper and have a rotating table to spray finish off of the lathe also for bowls or platters.
I do have a nice card style I use at the lathe, mainly for quicker touch up on the skew.

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#8 ·
I use my 1" belt sander. I had to clean up some Plexi and Acrylic disks and the carbide wasn't doing well, so I touched it to the belt for less than a second and it sharpened it so well I didn't have to sand and polish them.

Round might be more of a challenge, but I'd just mount them on a screw with a nut to lock them down, mount them in a 120 volt drill (faster speeds than a cordless) and run them for a second.
 
#9 ·
Carbide inserts were not meant to be resharpened; just replaced. True, you can touch them up a little since you are working with wood, not hardened steel. If you check with a metal working supply, (there are many) you can find inserts of any size and shape and they will probably be less expensive than those sold by the woodworking suppliers. A lot of inserts come from China and are a good deal. Try MSC, Travers, Wholesale Tool, etc.
 
#10 ·
MrRon, I could not count the number of times I was told I could not do something, after I'd done it. The first example I remember was, I was covering vertical surfaces with two part epoxy. I was buying it in five gallon containers. I was years into it before I learned "I couldn't."

As I mentioned above, I was cleaning up some colored Acyrlic I'd cut using a hole saw. Before going after them with my carbide tip, it was taking a long time to work my way through sand paper and polish. After switching to the carbide, it was a turn key project, so to speak. However, I tried the HSS scraper and it didn't do the job. Neither did the carbide, until I touched it on the sander (220) for just a second.

How would it be we can sharpen saw blades over and over again, but not carbide lathe knives?
 
#12 ·
MrRon, I could not count the number of times I was told I could not do something, after I d done it. The first example I remember was, I was covering vertical surfaces with two part epoxy. I was buying it in five gallon containers. I was years into it before I learned "I couldn t."

As I mentioned above, I was cleaning up some colored Acyrlic I d cut using a hole saw. Before going after them with my carbide tip, it was taking a long time to work my way through sand paper and polish. After switching to the carbide, it was a turn key project, so to speak. However, I tried the HSS scraper and it didn t do the job. Neither did the carbide, until I touched it on the sander (220) for just a second.

How would it be we can sharpen saw blades over and over again, but not carbide lathe knives?

- Kelly
Pretty much my thoughts too. One thing though, I thought carbide was harder than most sanding grits, other than Greenstone and diamond. What does it do to your sanding belt/disc after you do your sharpening.

I will never have to buy another carbide cutter since I set up my grinder described in my post #4. I didn't say that I only grind the top of the cutters, not the edges. ............ Jerry (in Tucson)
 
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